A PC (Physical Contact) fiber optic connector features a slightly curved end face that allows direct contact between fiber cores, reducing air gaps and enabling reliable optical connections.

Definition and Structure

A PC connector is a type of fiber optic connector where the end face is polished to achieve physical contact between two fiber cores. The end face is slightly convex, with the fiber core positioned at the highest point of curvature. This design minimizes the air gap between connected fibers, improving light transmission and reducing signal loss compared to older flat-polished connectors ( ).

Performance

• Return Loss: PC connectors typically have a return loss of around -40 dB, which is higher than the original flat polish style but lower than UPC (-50 dB) and APC (-60 dB) connectors ( ).
• Insertion Loss: The physical contact reduces insertion loss by ensuring better alignment of fiber cores.
• Durability: While PC connectors are stable and reliable, repeated mating can degrade the surface over time, which is why UPC and APC connectors are often preferred for high-performance applications ( ).

Comparison with UPC and APC

• UPC (Ultra Physical Contact): An improved version of PC with a more pronounced convex dome, offering better surface finish and lower return loss (~-50 dB). Suitable for most digital and analog transmission systems ( ).
• APC (Angled Physical Contact): Features an 8° angled end face to minimize back reflection, achieving the lowest return loss (~-60 dB). Ideal for RF, CATV, and high-frequency applications ( ).

Applications

PC connectors are widely used in data centers, LANs, MANs, and general fiber optic communication systems where moderate return loss is acceptable. Standard connector types such as SC, FC, and ST often adopt PC end face polishing ( ).

Summary

The PC fiber optic connector is a foundational connector type that ensures physical contact between fiber cores, reducing air gaps and providing reliable optical performance. While largely replaced by UPC and APC in high-performance systems, PC connectors remain cost-effective and suitable for many standard communication applications ( ).